Operation and calibration of polarimeter

1.0 Purpose
1.1 To describe a procedure for operation and calibration of Polarimeter.

2.0 Scope
2.1 This standard operating procedure is applicable for operation and calibration

of Polarimeter located at Chemical Room in Quality Control laboratory at ABC Pvt. Ltd., Roorkee .

3.0 Responsibility
Officer QC/ Executive QC Preparation of SOP and follow the procedure as per SOP
Assistant Manager Reviewing and Training of SOP
Manager QC Implementation of SOP
4.0 Accountability
4.1 Manager Quality Control is accountable for implementation and compliance with SOP.

5.0 Procedure
5.1 Operation
5.1.1 Ensure that all the parts including optical lens, telescope lens, and Polarimeter tube are clean.
5.1.2 Switch on the instrument and warm up sodium lamp to its maximum brightness.
5.1.3 Set the alignment of the sodium lamp compartment to the optical bench.
5.1.4 Ensure that all the setting of scale should be in zero position.
5.1.5 Open the Polarimeter tube compartment and place the Polarimeter tube, which is filled

with solvent in which sample is prepared in such a way as to avoid air-bubbles.
5.1.6 Observing through telescope when the half darkened and half light portions of a

circle are in equilibrium does observation.
5.1.7 This half dark and half light portion is matched with a knob by rotating it in clockwise

or anti-clockwise direction. It is also defined as dextro (+) or levo (-) rotator respectively.
5.1.8 Note the observed readings and also perform a sample determination in the same manner.
5.1.9 Calculate the difference of angle of rotation of sample and blank.
5.1.10 Calculate the specific optical rotation of the sample at 250C by the following formula

α = angle of rotation,
L = length of Polarimeter tube,
C = concentration of solution in %
5.1.11 Record the observations of instruments on Usage of Logbook.

5.2 Calibration (Frequency: after 6 Months)
5.2.1 Switch on the instrument and warm up the sodium lamp to its maximum brightness.
5.2.2 Operate the instrument as per 5.1.2 to 5.1.7
5.2.3 Now fill the Polarimeter tube with 10% w/v solution of sucrose (dried) carry out the

determination in the similar manner as blank.
5.2.4 Repeat the step g. for 20, 30, 40 and 50% w/v concentration of sucrose solution.
5.2.5 The table containing concentration and corresponding angle of rotation in a 2-dm tube at 25°C are indicated below.

Concentration gm/100 ml	Angle of rotation (+) at 25°C
10.0	+13.33^o
20.0	+26.61^o
30.0	+39.86^o
40.0	+53.06^o
50.0	+66.23^o

5.2.6 Document the activity in Calibration Record of Polarimeter Format (Annexure I).
5.2.7 Fill the Calibration Tag and affix it on the instrument.
5.2.8 Clean the instrument and keep under cover when not in use.
5.2.9 Report any discrepancy observed during calibration of instrument to Quality

Control- Manager or his designee for corrective and preventive action.
5.2.10 Quality Control- Manager or his designee informs the defect to Maintenance

Department service engineer to rectify the defect. Affix ‘Under Maintenance’ label on the instrument.
5.2.11 Calibration should be required after maintenance.

5.3 Cleaning
5.3.1 Clean the instrument with dry cloth to remove the dust before and after use.

6.0 Reference
Indian Pharmacopoeia

7.0 Attachments
Annexure I : Calibration Record of Polarimeter

8.0 Distribution
Distribution of the controlled copy to concerned departments.
Additional copies may be issued for specific purpose.

9.0 Abbreviations
QA : Quality Assurance
QC : Quality Control
SOP : Standard Operating Procedure
SOR : Specific Optical Rotation
°C : Degree Centigrade
° : Degree
gm : Gram
ml : Milli Liter
+ : Positive

10.0 Revision History